Tube end forming device



Jan. 11, 1966 Filed Dec. 5, 1962 3 Sheets-Sheet 1 m z/4/ 114 4 4 M 7 INVENTOR.

ROBERT J. MYOTTE .2 ATTOR EYS Jan. 11, 1966 R. J. MYOTTE 3,228,228

TUBE END FORMING DEVICE Filed Dec. 5, 1962 3 Sheets-Sheet 2 INVENTOR. ROBERT J. MYOTTE ATTORNEYS Jan. 11, 1966 J, Yo 3,228,228

TUBE END FORMING DEVICE Filed Dec. 5, 1962 l 3 Sheets-Sheet 5 FIG. 5

l8 l9 L- l8 INVENTOR. ROBERT J. MYOTTE United States Patent() 3,228,228 TUBE END FORMING DEVICE Robert J. Myotte, Solon, Ohio, assignor to National Copper Development Company, Solon, Ohio, 2 corporation of Ohio Filed Dec. '3, 1962, Ser. No. 242,004 7 Claims. (Cl. 72-402) This invention relates in general to swaging apparatus and more specifically to an improved arrangement for shaping or forming the end of a length of tubing.

In preparing tubular stock for various types of drawing operations the forward end of the stock is usually swaged down and pointed for insertion into the drawbench carriage gripping jaws. At present this swaging operation is accomplished through the use of a variety of pieces of apparatus, one of which is the rotary swaging machine. However the various pieces of apparatus used at present to perform this operation are not wholly satisfactory when considered from such practical standpoints as cost of manufacture, simplicity of construction, ease of assembly and disassembly for maintenance and repair, and length of operation time cycle. It is therefore a principal object of this invention to provide a tube forming apparatus which constitutes an improvement over the swaging devices known and used heretofore from the standpoints noted.

For example, present swaging and pointing apparatus used to prepare the ends of tubular stock for drawing operations requires that the stock be fed into. the machine in incremental amounts until the desired length has been swaged. This is undesirable since it is a somewhat laborious and time-consuming procedure. Accordingly, another object of this invention is to provide apparatus which will enable the swaging of tubular stock to be accomplished more quickly and easily than is possible through the use of apparatus presently known and generally used.

Another undesirable feature which attends apparatus presently known and used for swaging operations is that such apparatus is rather complex, expensive and generally not useful for other metal working operations. Thus an investment in such highly specialized equipment, the usefulness of which is rather limited, is a disadvantage which it is an object of the present invention to overcome. For the apparatus of the present invention is of simple, durable construction and may be used on and with many of the well-known standard punch presses presently in use.

In order to achieve the foregoing objects and others which will become apparent to those skilled in the art, the present invention contemplates a new, inexpensive and simple form of die construction and arrangement which will enable the entire swaging operation to be performed by one stroke of a press.

Briefly, to achieve these ends, the apparatus of this invention which may be installed on a conventional power press, comprises a bolster die block mounted on the bolster of the press and having inclined wall portions in which a pair of mating side die members are fitted in faceto-face relation for vertically inclined movement. The inner face of each side die member is provided with inclined and vertical surfaces, with a portion of each vertical surface being adapted to support a work forming lower die which maintains the side die members in spaced relation, thereby forming a Y-shaped cavity therebetween. Mounted to the press ram is a work forming upper die adapted to press the tubular stock from its cradled position in the apex formed between the inclined surfaces of the side die members into the relatively narrow cavity formed between the vertical walls of the side die members, thereby effecting a first stage of forming of the tubular stock. The second and final forming stage is effected when the tubular 3,228,228 Patented Jan. 11, 1966 stock is pressed against the work forming lower die which is positioned at the bottom of the Y-shaped cavity.

The features of this invention which are considered to be novel are set forth with particularity in the appended claims. The foregoing objects as well as additional objects and advantages of the invention will be readily apparent in the course of the following detailed description taken in connection with the accompanying drawings which illustrate by way of example, a preferred embodiment of the invention, and wherein:

FIG. 1 is a perspective View, partly in section, of the tube end forming apparatus of the present invention;

:FIG. 2 is a vertical sectional view taken substantially along line 22 of FIG. 1;

FIG. 3 is a vertical sectional view taken substantially along line 3-3 of FIG. 1 but showing the apparatus in the last stage of forming the end of a tubular stock workpiece;

FIG. 4 is a vertical sectional view taken substantially on line 44 of FIG, 3; and

FIG. 5 is a vertical sectional view similar to FIG. 4, but showing the second stage of forming the end of a tubular stock workpiece within a modified form of the apparatus f this invention.

Referring now to the drawings, in which like reference characters denote like parts, the apparatus embodying the principles of the present invention is adapted to be used in connection with a press, generally indicated by the reference numeral 10, which includes a vertically shiftable ram 12, and bolster 13. Since th present invention has only to do with the apparatus mounted on the press, a further and more elaborate showing of the press itself is considered to be unnecessary for a complete understanding by those skilled in the art.

Referring now in detail to FIGS. 1 and 2, a die block 14 having inwardly inclined wall portions 16 which form an elongated trough-shaped depression or recess is shown suitably secured on bolster 13 of press 10. Positioned within the trough-shaped depression of block 14 for vertically inclined movement are a pair of elongated mating side die members 18, the sloping sides 19 of which are complementary to and rest in engagement with the inclined wall portions 16 of block 14. As best shown in FIGS. 1 and 3, each of side die members 18 has the same length as die block 14 and is retained at each end within the trough of block 14 by retaining plates 20, 22 which are secured thereon by screws 24. In order that the forward end of a length of tubing 30 may be received and cradled in the forming apparatus of the present invention, a V- shaped opening is formed in the face of plate 22 through which the remaining portion of tubing 30 may extend outwardly there beyond.

As best shown in FIG. 2 each of side die members 18 has corresponding inclined and vertical surfaces 31 and 33 respectively, which, when the members are arranged in the position shown, form a Y-shaped cavity between the members. At the lower portion of each vertical surface 33 of members 18, a ledge 26 is provided which, when members 18 are positioned within block 14 form a seat on which a workpiece forming first or lower die or die insert 28 rests.

As illustrated in FIGS. 2 and 3, lower die 28 is of the same length as members 18 and is formed with a hat bottom surface which rests squarely and securely on each of ledges 26. The upper surface of lower die 28 is concave in cross section throughout its length to receive the convexly curved surface of a portion of tube 30 in a manner and under conditions presently described.

The width of lower die 28 is such as to just contact vertical surfaces 33 of side die members 18 when said side die members are bottomed on floor 35 of die block 14. Resilient means 37, such as the springs shown in FIGS. 2 and 4, are provided to cushion and bias side die members away from floor 35 when not under pressure of ram 12 and workpiece forming second or upper die 32. A dual purpose is served wtih this arrangement. First, the biasing means tends to relieve stresses at the corners of ledges 26 and vertical surfaces 33 during the downward stroke of ram 12. Second, the resilient means 37 shift the side dies apart during the return stroke of the ram 12 to facilitate easy removal of the workpiece 30 at the completion of the forming operation.

Referring again to FIGS. 1 and 2, the upper forming die 32, which is of the same length and width as insert 28 is shown positioned above the Y-shaped cavity formed between members 18 and in parallel and vertical alignment with insert 28. Upper forming die 32 is similar in contour to insert 28 in that it is shaped along its underside to refiect the concave contour of the upper surface of lower forming die 28. It is secured to ram 12 by nuts 34 and bolts 36, within the longitudinal channel of ram 12 which forms a part of press 10. Ram 12 in turn is attached to a suitable mechanism (not shown) for lowering and raising die 32 into and out of the Y-shaped cavity between members 18.

In order to avoid unduly stressing and thus possibly weakening the walls in the area between the formed and unformed portions of tubing 30, a conical transition portion 39 is formed there between. This is achieved, as illustrated in FIG. 3, by providing tapered portions on upper die 32 and lower die 28 in the area adjacent plate 20 so that their concave surfaces diverge from the center of the Y-shaped cavity.

The extent to which the formed portion of the tubing 30 will be reduced is determined by the width of lower die 28 and by the distance upper die 32 is permitted to move down into the Y-shaped cavity formed between members 18. As indicated previously, the width of insert 28 determines the width of the space between the corresponding vertical and inclined surfaces of die members 18. As will be presently described in connection with the operation of this invention, the second and final reduction stage in the swaging of tube 30 occurs after the tubing has been pressed oval shaped (see FIGURE 4) between the vertical walls 33 of members 18 and into engagement with the concave surface of lower die 28. At this point the cross sectional width of tube 30 is substantially equal to the width of lower die 28 with the cross sectional height of the tube being determined by the final distance between the concave surfaces of lower die 28 and upper die 32. Further downward movement of ram 12 collapses the side walls of tube 30 to assume the figure eight configuration shown in FIGURE 5 of the drawings.

In operation the portion of tubing 30 to be end formed for drawing is placed within the apex formed by the inclined surfaces of die members 18 and is positioned therein with its end in abutment with retaining plate 20. The remaining length of tubing 30 which is not to be swaged projects outwardly through the V-shaped opening in plate 22. With the tubing mounted in the position described above and shown in FIGS. 1 and 2, the mechanism controlling the movement of ram 12 is actuated to lower die 32 into engagement with the upper surface of tubing 30. As the pressure exerted by die 32 increases, tube 30 is pushed between the vertical walls of members 18 which are spaced apart by a distance which is determined by the width of lower die 28 and which is less than the diameter of the tube. As a result of being pressed into this portion of the Y-shaped cavity, the first stage of the swaging operation is completed in that the cross sectional configuration of tubing 30 becomes and remains oval or egg-shaped until the under-surface of the tubing is forced into contact with the concave surface of lower die 28. When this contact with insert 28 is effected, the periphery of tubing 30 is completely enclosed within the forming dies. The continued exertion of pressure by upper die 32 against tubing 30 causes the sides of the tubing which are in substantial abutment with the vertical walls of members 18 to collapse and fold inwardly toward each other as shown in FIG. 5. Upper die 32 continues to collapse tube 30 until the cross section of the formed end is substantially circular. Resilient means 37 then urge side die members upwardly upon release of pressure by ram 12 during its return stroke, permitting the workpiece 30 to be easily removed.

Although the present invention has provided an apparatus for forming the ends of tubular stock, it is to be understood that the form selected to facilitate the disclosure of the invention is not intended to limit the number of forms it may assume or the number of applications in which it may be employed. Moreover, it is to be further understood that various modifications, adapta tions and alterations may be applied to the specific form shown to meet the requirements of practice, without in any manner departing from the spirit or scope of the present invention.

Having described my invention, what I now claim is:

1. An apparatus for forming a tubular workpiece comprising, a die block having an elongated trough, a pair of side die members positioned within and extending throughout the length of said trough, said side die members being vertically shiftable within said die block trough, each of said members being provided with inclined and vertical surfaces arranged in spaced relation to form a Y-shaped cavity between the lengths of said members, and said vertical surfaces being spaced apart less than the diameter of said workpiece, a first die positioned between a portion of the vertical surfaces of said members, and a second die arranged to press said tubular workpiece from a cradled position between the inclined surfaces of said members into the space between said vertical surfaces and subsequently against said first die.

2. An apparatus for forming a tubular workpiece comprising, a die block having an elongated trough, a pair of spaced apart side die members mounted for shiftable vertical movement within said trough and provided with inclined and vertical portions on its inner surfaces, :1 first die positioned between and having side portions in engagement with the vertical portions of said side die members when shifted to the bottom of said trough for retaining said members in a predetermined spaced apart relationship, whereby said inclined portions are arranged to cradle said workpiece and said vertical portions are spaced apart by a distance which is less than the width of said workpiece, and a second die arranged to move into and out of the space between said side die members for forcing said workpiece into the space between the vertical portions of said side die members and against said first die.

3. An apparatus for forming a tubular workpiece comprising, a die block having an elongated trough, a pair of laterally spaced apart elongated side die members adapted along their outer side surfaces for sliding contact with said trough and provided on their inner sides with an inclined surface adjacent one edge, a ledge portion formed along the opposite elongated edge of said inner side, and a vertical surface portion formed between said inclined surface and said ledge portion; an elongated first die having a transversely concave surface portion throughout its length and having a predetermined width which is less than the diameter of said workpiece, said members being retained in spaced apart relation within said recess when said first die is positioned on the ledge portions and between the vertical surface portions of said members, said first die being positioned on said ledge portions and extending throughout the length of said die members with its concave surface portion projecting vertically, and with its side portions in engagement with the vertical surfaces of said side die members when said side die members are bottomed in said trough, a second die arranged to press said tubular workpiece from a cradled position between the inclined surfaces of said side die members into the space between said vertical surfaces and against the concave surface of said first die, and means to normally bias said side die members vertically.

4. A die for forming the end length of tubular stock comprising, a die block having an elongated trough with an open end, a pair of transversely spaced apart vertically shiftable elongated side die members mounted within said trough, there being longitudinally joining inclined and vertical surfaces extending throughout the length of the inner side of said side die members, an elongated die insert positioned between the vertical surfaces of said members for spacing said members and forming a Y- shaped cavity therebetween, an elongated forming die arranged to move into and out of said cavity opposite the die insert for pressing said stock through said Y- shaped cavity and against said die insert, said die insert and forming die having transverse concave surfaces facing toward each other and into said cavity, and matching tapered portions on said opposed die insert and forming die for effecting a divergent transition of said concave surfaces adjacent the open end of said die block, the divergence being such as to form a transition taper between the formed and unformed portions of said stock.

5. An apparatus for forming a tubular workpiece comprising, a die block having a trough with inwardly inclined wall portions, a pair of transversely spaced apart side die members positioned within said trough, means for resiliently supporting said side die members within said trough for vertically inclined movement along the inclined wall portions of said trough, said side die members being provided with oppositely facing upper inclined and lower vertical surfaces arranged to form a Y-shaped cavity there between, a lower die positioned Within said Y-shaped cavity and retaining said vertical surfaces in a predetermined spaced apart relation less than the diameter of said workpiece, and an upper die arranged to press said workpiece into said Y-shaped cavity and against said lower die to collapse the side walls of said tubular workpiece into a cylindrical configuration of less diameter than its initial diameter.

6. An apparatus for forming a tubular workpiece comprising, a die block having a trough with inwardly inclined wall portions, a pair of transversely spaced apart mating side die members positioned within said trough and provided on their inner sides with upper inclined and lower vertical surfaces, a lower die positioned between the vertical surfaces of said members and retaining said members in spaced apart relation whereby a Y-shaped cavity is formed there between, said lower shaping die being formed to space apart said vertical surfaces a distance which is less than the diameter of said workpiece, a resilient member positioned at the bottom of said trough and under said side die members for resiliently supporting said members for vertically inclined movement along the inclined wall portions of said trough, and an upper die arranged to press said workpiece from a cradled position between the inclined surfaces of said side die members into the space between said vertical surfaces and against said lower die.

7. A tube end forming device comprising:

(1) A die block having a V-shaped trough extending longitudinally from end to end;

(2) A pair of side die members having remote surfaces adapted to abut and slide on adjacent surfaces respectively of said V-shaped trough, and opposed surfaces forming a Y-shaped trough there between;

(3) Means to bias said side die members from the bottom of said die block V-shaped trough;

(4) A lower forming die freely positioned between said side die members at the base of said Y-shaped trough having a cross section less than the diameter of a workpiece;

(5 An upper forming die adapted to vertical reciprocal movement; and,

(6) Whereby pressure of said upper forming die against a workpiece placed in said Y-shaped trough urges said side dies downwardly and inwardly in sliding contact with said adjacent surfaces of said die block to compress and collapse the side walls of said workpiece, and whereinafter said biasing means urges said side dies upwardly and outwardly for easy removal of the formed workpiece.

References Cited by the Examiner UNITED STATES PATENTS 810,241 1/1906 Wikstrom 15370 1,070,379 8/1913 Summey 15370 1,775,432 9/1930 Jessen et al. 15370 1,994,725 3/1935 Offutt l5370 2,484,032 10/1949 Holm 15370 3,068,929 12/1962 Rowell 15370 3,154,978 11/1964 Baker 15370 CHARLES W. LANHAM, Primary Examiner. 

1. AN APPARATUS FOR FORMING A TUBULAR WORKPIECE COMPRISING, A DIE BLOCK HAVING AN ELONGATED TROUGH, A PAIR OF SIDE DIE MEMBERS POSITIONED WITHIN AND EXTENDING THROUGHOUT THE LENGTH OF SAID TROUGH, SAID SIDE DIE MEMBERS BEING VERTICALLY SHIFTABLE WITHIN SAID DIE BLOCK TROUGH, EACH OF SAID MEMBERS BEING PROVIDED WITH INCLINED AND VERTICAL SURFACES ARRANGED IN SPACED RELATION TO FORM A Y-SHAPED CAVITY BETWEEN THE LENGTHS OF SAID MEMBERS, AND SAID VERTICAL SURFACES BEING SPACED APART LESS THAN THE DIAMETER OF SAID WORKPIECE, A FIRST DIE POSITIONED BETWEEN A PORTION OF THE VERTICAL SURFACES OF SAID MEMBERS, AND A SECOND DIE ARRANGED TO PRESS SAID TUBULAR WORKPIECE FROM A CRADLED POSITION BETWEEN THE INCLINED SURFACES OF SAID MEMBERS INTO THE SPACE BETWEEN SAID VERTICAL SURFACES AND SUBSEQUENTLY AGAINST SAID FIRST DIE. 